fix: always prepend bogus header to fool firmware into accepting the print (CURA-520)
fix: always prepend bogus header to fool firmware into accepting the print (CURA-520)

this was done so that Jedi gcode also always includes a header
it also means that UMO gcode always gets a header, which is ok, as it is ignored by that firmware

totalretribution/CuraEngine,alephobjects/CuraEngine,totalretribution/CuraEngine,totalretribution/CuraEngine,ROBO3D/CuraEngine,alephobjects/CuraEngine,Ultimaker/CuraEngine,alephobjects/CuraEngine,ROBO3D/CuraEngine,Ultimaker/CuraEngine,ROBO3D/CuraEngine